1. Field of the Invention
This invention generally relates to a headset for a bicycle. More specifically, the present invention relates to a headset for attaching a fork column of bicycle front fork to a head tube of a bicycle.
2. Background Information
Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle. One component that has been extensively redesigned is the bicycle headset.
A front fork for a bicycle is attached to a head tube so as to be able to rotate freely. At both ends of the head tube are ball bearings. Male threads are provided on an upper end of the fork column of the front fork. A handle stem is attached to the male threads. A headset is attached to the fork column to secure the front fork to the head tube. Conventional headsets have lock nuts that lock upper ball bearing retainers. The upper ball bearing retainers mate to male threads on the outer periphery of the fork column. (See, for example, U.S. Pat. No. 5,330,220.)
However, recently front forks that do not have male threads on the fork column have been widely used. With this type of front fork, the fork column protrudes upward from the head tube and the handle stem is attached on the protruding fork column. In this type of conventional headset, there is a lock nut and an adjustment bolt, which mates with the lock nut. A cover member is attached by the adjustment bolt to the top part of the handle stem. A compression ring with a slit is disposed between the fork column and an upper ball bearing retainer. (See, for example, U.S. Pat. No. 5,095,770.)
In a conventional headset having this type of structure, after the compression ring and the handle stem are placed onto the fork column, the cover member is put onto the top part of the handle stem. The adjustment bolt is then mated to the lock nut to attach the front fork to the head tube. The ball bearing contact is adjusted by tightening or untightening the adjustment bolt after inserting and tightening the compression ring between the fork column and the ball bearing retainer. The height of the handle stem is adjusted by adding ring-shaped spacers between the handle stem and the upper ball bearing retainer and between the handle stem and the cover member.
In the conventional headset described above, the ball bearing contact is adjusted by the handle stem. The handle stem applies pressure to the upper ball bearing retainer through the cover member. Thus, it is necessary to have a separate member, such as a ring-shaped spacer for adjusting the height of the handle stem. Because of this, the adjustment of the height of the handle stem is difficult. Moreover, because the pressure is applied to the ball bearing retainer through the handle stem, the pressure is removed from the ball bearing retainer when the handle stem is removed. Because of this, it is necessary to adjust the ball bearing contact each time the handle stem is removed.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved bicycle headset that allows adjustment of the ball bearing contact independent of the handle stem. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.